The Symbiq™ infusion system, made by Hospira, Inc., previously detected whether air was present in the infusion system by operating one or more sensors at their resonant frequency, which was determined and set during calibration. The one or more sensors were used to transmit and receive a signal through a fluid delivery line of the infusion system in order to determine, based on the strength of the signal that propagated through the fluid delivery line, whether air, fluid, or some combination thereof was disposed in the fluid delivery line. Signals propagate better through liquid fluid than through air. The resonant frequency of the one or more sensors is the frequency at which the output of the signal transmitted from the one or more sensors is maximized for a given transfer medium such as for the infusion fluid contained within the fluid delivery line of the infusion system. Thus, conventional wisdom suggested that the one or more sensors would be most effective at their resonant frequency. However, analog-to-digital converters are used to convert the received analog signal from analog to digital in order for a processor to determine, based on the converted digital signal, whether air, fluid, or some combination thereof is disposed in the fluid delivery line of the infusion system. It has been observed or discovered by the Applicants that under certain conditions, analog-to-digital converters can become over-saturated if the output of the signal transmitted from the one or more sensors is too high.
A system and method is needed to overcome one or more issues of one or more of the existing systems and methods for detecting air in an infusion system.